Ammonolysis of organosilicon halides



Patented Dec. 18, 19511 UNITED STATES PATENT OFFICE AMMONOLYSIS FORGANOSILICON HALIDES Nicholas D. Cheronis, Chicago, 111., assignor oione-third to Edwin L. Gustus, Chicago, 111.

No Drawing. Application August 7, 1947, Serial No. 767,332

nia or a gaseous substituted amine.

Another object 'of my invention is the production of ammonolyzed siliconcompounds by reacting an aromatic silicon halide with gaseous ammonia ora gaseous substituted amine.

A further object of my invention is the production of a polymerizedsilicon resin containing NH: and/or NH groups directly linked to 14Claims. (01. 260-2) the silicon atom, with the silicon atomsinterconnected by --N groups.

Still another object of my invention is an ammonolyzed silicon resincapable of rapid but controllable polymerization.

Other objects and advantages of my invention will become apparent as thefollowing description of my invention proceeds.

U. S. patent application Serial No. 616,475, Nicholas D. Cheronis,Silicon Polymers, filed September 14, 1945 (now abandoned in favor ofcontinuation-impart application Serial No. 72,548, Nicholas D. Cheronis,Polymeric Resinous Products Containing Repeating Units of Silicon Linkedto Nitrogen and Process for Making Same," filed January 24, 1949) andapplication Serial No. 643.494, Nicholas D. Cheronis and Edwin L.Gustus, Preparation of Polymers,

filed January 25, 1946, describe methods of ammonolyzing organic siliconhalides; application Serial No. 613,009, Nicholas D. Cheronis,Watar-Resistant Leather, filed August 27, 1945 (now abandoned in favorof continuation-inpart application Serial No. 56,663, Nicholas D.Cheronis, Resin-Impregnated Water-Resistant Leather, filed October 26,1949), and application Serial No. 643,493, Nicholas D. Cheronis,"Leather Treatment, describe the application of hydrolyzed and/0rammonolyzed organic silicon halides to leather. The present inventiondeals with novel methods of making ammonolyzed organic silicon halidesof the general structure disclosed in these applications, and with newand useful resins prepared therefrom.

A silicone resin is generally understood to be 2 a polymeric compoundcorresponding to the type formula where It stands for an aliphatic oraromatic radical, and where Y stands for an aliphatic or aromaticradical or a hydroxyl group. Such a resin is formed by the condensationof organosilicon hydroxy compounds of the type formula RmSi (OH) 4-1:

wherein n does not exceed 2, which in turn are the hydrolysis productsof an organic halosilane of the type formula RnSlHdh-n wherein n alsodoes not exceed 2. Cross linkages within the polymer group may reduce oralmost entirely eliminate the hydroxyl groups and replace them bygroups.

If organic halosilanes are ammonolyzed in accordance with my invention,and polymerized, organic polymers of the type formula are formed,wherein silicon atoms are interconnected by NH groups and free siliconvalences at either end of the polymeric group have NH: groups attachedthereto. The starting material for such compounds, are again the organichalosilanes oi the type formula which are treated with ammonia or asubstituted amine to substitute the halogens by NH: groups.Polymerization to the above-described compounds takes place bycondensing 3 silicon-attached NH: groups to NH groups, with evolution offree ammonia. Cross linkages in the polymeric groups of the polymerizedammonolyzed'silanes further reduce or almost entirely eliminate NH:groups bonded to silicon with formation of cross linkages R a iat-A151-in in -N-ai-N-s1-N- nv H H oups.

I have discovered that an organic halosilane may be converted into acorresponding ammonolyzed compound by dissolving it in an organicsolvent which is inert towards the organic halosilane (i. e., does notreact with it) and reacting it with gaseous ammonia (unsubstituted orsubstituted) in the absence of water or moisture and under conditionsabout to be described, and permitting the resulting amino silanes topolymerize to the desired degree. Suitable aliphatic solvents areethers, such as ethyl ether or propyl ether, while suitable aromaticsolvents are toluene or xylene. Organic halosilanes suitable in thereaction are, for instance, mono-, dior tri-chlorides, bromides, iodidesor fluorides of a silane substituted with respectively 3, 2, or 1 alkylor aryl group. If more than one organic group is attached to the siliconatom, such organic groups need not be identical. Suitable asammonolyzing agents, in addition to gaseous ammonia, are such compoundsgaseous at room temperature as methylamine, ethylamine and other relatedcompounds. In fact, all nitrogen compounds containing at least tworeplaceable hydrogen atoms directly bonded to a nitrogen atom aresuitable for reaction with the silicon compound, so long as care istaken not to introduce any groups into the compound which will preventpolymerization by steric hindrance. To obtain polymerizable compounds, adior tri-halogenated organosilane is selected as starting material,inasmuch as hydrolyzed or ammonolyzed monochloro-organosilanes form onlydimers:

In addition to methyl trichlorosilane, dimethyl dichlorosilane, diethyldichlorosilane, ethyl trichlorosilane, ethyl tribromosilane, ethyltriiodo silane, ethyl trifluorosilane, ethyl dichloro monofluorosilane,propyl tribromosilane, butyl tri-iodo silane, n-propyl trichlorosilane,dipropyl dichlorosilane, isopropyl trichlorosilane, n-butyltrichlorosilana isobutyl trichlorosilane, isoamyl trichlorosilane,benzyl trichlorosilane, naphthyl trichlorosilane, amyl ethyldichlorosilane, propenyl trichlorosilane, phenyl trichlorosilane,diphenyl dichlorosilane, methyl ethyl dichlorosilane, phenyl methyldichlorosilane, dibenzyl dichlorosilane, p-chlorophenyl silicontrichloride, n-hexyl trichlorosilane, cyclohexyl trichlorosilane,dicyclohexyl dichlorosilane, diisobutyl dichlorosilane, paratolyltrichlorosilane, di-para-tolyl dichlorosilane, parastyryltrichlorosilane, ethynyl trichlorosilane,

I awaeiz which are mono-alkyl, di-alkyl, allql-aryl and 'allq'lchlorosilane) di-aryl halosilanes whose ammonolysis is described in theabove-enumerated earlier applications, we find that suchorganichalosilanes as allyl trichlorosilane, and di-allyl dichlorosilane(halosilanes containing unsaturated alkyl groups) n-dodecyltrichlorosilane (along-chain p-anisyl trichlorosilane, and para-ethoxyphenyl trichlorosilane (chlorosilanes containing aromaticoxy-substituted groups) can be ammonolyzed and polymerized in accordancewith the present invention. I

Thus, as set for in the copending application Serial No. 72,548,Nicholas D. Cheronis,'the repeating units of the polymerized resinconsist of silicon to which are attached hydrogen-substituted orhydrocarbon-substituted nitrogen atoms as links to the adjacentrepeating units; of the remaining valence or valences of the silicon aretaken up by a monovalent hydrocarbon radical. If a tri-functionalsilane, that is an organosilane having one monovalent hydrocarbonradical and three halogen atoms on the silicon atom, is selected as thestartingmaterial, the ammonolysis and subsequent condensation inaccordance with the present invention will result in a cross-linkedresin, in which each repeating unit consists of a silicon atom to whichthe monovalent. hydrocarbon radical of the starting material remainsattached, and which shares with the adjacent repeating units 'threehydrogen-substituted or hydrocarbon substituted nitrogen atoms.

Hal l l R ammono ss RiHal 4i-N i-N i- 1k condensation II I I .siliconatom, such as diethyldichlorosilane, is

ammonolyzed and condensed in accordance with my invention by followingthe just-described process of reacting the organosilane in the presenceof an inert solvent such as ether and in the absence of water, with anexcess of'liquid ammonia or primary amine wherein the amino group is thesole functional group, followed by partial condensation in solution, theresulting polymeric product is characterized by repeating units whereintwo monovalent hydrocarbon radicals are attached to the silicon atom andthe remaining two valences of the silicon atom are taken up byhydrogen-substituted or hydrocarbon-substituted nitrogen links to theadjacent repeating unit.

R ammonolysis i Nii Niii condensation 1!2 l R HalSiHal R Three preferredexamples or ammonolysis and polymerization in accordance with thepresent invention will now be given by way'oi illustration:

Example I A three neck flask squipped with mechanical stirrer andcontaining 500 ml. of dryether is immersed into a cooling bath; thelatter can either be an intimate mixture of ice and salt or Dry Ice andmethanol. Through one of the necks fits a separatory iunnel containing100 grams of an aliphatic chlorosilane, tor-example.

diethyl dichlorosilane, in 500 ml. of dry ether and through the otherthe inlet, tube for ammonia gas. The stirrer is started until thetemperature of the ether within the flask reaches about -10 C. and thengaseous ammonia is introduced while the solution of chlorosilane isadmitted dropwise through the ether ammonia mixture. The addition of thereactants is so controlled as to maintain a temperature substantiallybelow C. Ammonolysis takes place with separation of ammonium chlorideand formation of the organosilicon amino compound according to theformula:

The addition of the chlorosilane and the action of the stirrer iscontrolled so as to insure an excess of ammonia within the reactionmixture at all times and also avoid a rise in temperature much above 0C. Completion oi the reaction is indicated by a rapid ialling oi the temperature of the reaction mixture. The contents of the flask are nowfiltered to remove the ammonium chloride, and the residue is washed withether so as to remove the adhering organosilicon amine compound. Astable solution is obtained by removing all or part of the ether andadding an appropriate amount, say 100 grams, oi water-free xylene. Theremoval of ether or concentration is best done under reduced pressureand at a temperature below 50 C. Other hydrocarbon solvents which areinert towards the aminosilicon compounds formed are suitable, as forexample, hexane and toluene. To avoid undesired hydrolysis of theaminosilicon compounds, it is necessary that the reaction takes place inthe absence of moisture and that anhydrous solvents be used. The productformed is stable in solutions of organic solvents with which theorganosilicon amino compound does not react and so long as reasonablecare is exercised that moisture is excluded from the solution. The yieldis about 90-95% of the theoretic as determined by evaporating in a watchglass a known amount of the solution at about 60 to 100 C. anddetermining the monia. giving high-molecular polymers which areinsoluble in organic solvents and are very stable. In this respect, thistype of compounds varies widely from the hydroxy organosilicon compoundswhich require heat for polymerization.

Example I! Aneck flask surrounded by an ice-salt bath and equipped witha stirrer is charged with 100 grams of an aromatic chlorosilane, forexample, p-ethoxy-phenyl trichlorosilane. and a large excess, say oneliter, of water-tree xylene: the solution is stirred until it reaches atemperature oi about +10 C. The reaction with gaseous ammonia is carriedout in the manner described in Example I.

After completion of the ammonolysis the aromatic silamine correspondingto the reacted aromatic chlorosilane is obtained. As no ether isintroduced into the system, no removal of ether takes place. The formedaromatic silamine-in-xylene solution is stable and represents a yield ofapproximately Care must be taken not to introduce water into the systemduring the reaction in order to avoid undesired hydrolysis. All aromaticsilicon halides enumerated in this specification may be thus ammonolyzedto silicon amines (silamines), including particularly phenyl triaminosilane (ammonolyzed from phenyl trichlorosilane), and diphenyl diaminosilane (ammonolyzed from diphenyl dichlorosilane) Example III Silaminesobtained by ammonolysis according to Example I are polymerized bycausing the solvent to evaporate or volatilize, e. g., by application ofmoderate heat, or exposure to air at room temperature. Resinous filmsare obtained, possessing the following characteristics:

(a) Polymerized dodecyl silicon triamine obtained by the ammonolysis andpolymerization of dodecyl trichlorosilane is a clear, soft, nontacky,pliable film.

(b) Polymerized allyl silicon triamine obtained by the ammonolysis andpolymerization of allyl trichlorosilane is a hard, brittle film.

(c) Polymerized diallyl silicon diamine obtained by the ammonolysis andpolymerization of diallyl dichlorosilane is an oily film, presumably dueto the absence of cross linkages at room temperature. At temperatures ofC. and higher, it turns into a hard and brittle film.

(d) p-Anisyl silicon triamine obtained by the ammonolysis of p-anisyltrichlorosilane polymerizes at room temperature to a brittle and hardfilm which, if heated to 100 C., turns yellow.

(e) Polymerized p-ethoxy phenyl silicon triamine obtained by theammonolysis and polymerization of ,p-ethoxy-phenyl trichlorosilane is abrittle and hard film at room temperature and does not change at 100 C.,but cracks and peels if heated to 200 C.

(f) Polymerized cyclohexyl silicon triamine, obtained by the ammonolysisand polymerization of cyclohexyl-trichlorosilane, is a non-tacw,flexible clear film, stable at 60 C. but becoming brittle upon heatingto about 200 C.

Other long-chain saturated hydrocarbon substituted' siiamine resinswhose properties are comparable to polymerized dodecyl silicon triamine(Example III (a) above) can be formed in accordance with my invention,e. g., by ammonolyzing and condensing an organosilicon compound of thetype RnsiH8-14n with at least two NH groups attached to the siliconatom, and unsaturated hydrocarbon radicals satisfying the remainder ofthevalences of the silicon atom.

Polymerized p-anisyl-triamine (Example 111 (d) above) and polymerizedp-ethoxy phenyl silicon triamine (Example III (e) above) are typical ofsilamine resins in which at least one alkoxy-substituted aromaticradical is attached to the silicon atom.

Polymerized cyclohexyl silicon triamine (Example III (I) above) is atypical silamine resin with one or more valences of the silicon atomsatisfied by an alicyclic hydrocarbon radical.

It will be understood that the corresponding fiuo'ro-, bromoandiodo-silanes may be substituted for the chlorosilanes mentioned in theabove examples. i

Mixtures of fully substituted organic silicon monoamines, diamines andtriamines can be so adjusted that the resin resulting from theirpolymerization possesses any desired properties with regard to hardnessor tackiness. Thus, an organic silicon triamine polymerized by itselfwill yield a harder and more brittle film than a mixture of apolymerized triamine with a diamine or monoamine. The resins'are toughand flexible and thus are eminently adapted for the impregnation ofleather, textiles. papers and other flexible materials, and they possessfav-- orable adhesive properties with regard to metal (e. g., steel),glass, etc. They are water repellent, though air permeable.

In order to carry out successfully the ammonolysis of organichalosilanes, it is necessary to maintain at all times during thereaction an excess of the ammonolyzing nitrogen compound, e. g., ofammonia. Likewise, it is necessary to carry out the reaction attemperatures substantially below room temperature; the most favorabletemperature differs with each individ-.

ual ammonolyzing nitrogen compound.

Polymerization of the organic silamines made in accordance withmyprocess takes place at temperatures somewhat above room temperature,in the neighborhood of 60 C. Even at room temperatures spontaneouspolymerization takes place upon exposure to the air for one or two days.Polymerization takes place by elimination of ammonia groups whichseparate out in gaseous form and may be collected by appropriatemeasures, e. g., in a hood. The polymerization, or rather condensation,of an synthesizing organosilicon compounds.

organic diamino-substituted silicon monomer may be represented by theformula murram %l- +mnn In the condensation of a. triamino-substitutedorganic silicon monomer, cross linkages by NH groups are formed:

Monoamino-substituted organic silicon monomers form only dimers: I

zmsuNrn) RJSLNILSiB-i NHIT A chief advantage of silamine condensation.as compared with the condensation of chloroare used as'synonymsthroughout the specification and claims.

I do not wish to limit myself to the foregoing specific examples ofmethods to prepare organic silamines in accordance with my invention,nor to any particular proportions of reactants, speeds. of reaction,etc. Modifications of my gaseous ammonia ammonolysis of organosiliconhalides in the absence of Water or moisture, within the spirit of myinvention, will readily occur to an expert skilled in the art ofLikewise, other silamines than those specifically enumerated in theforegoing specification and examples, e. g., homologues of the namedcompounds, may be prepared in accordance with my disclosure andthus arewithin the scope of my invention. I therefore desire to limit myinvention only by the appended claims.

I claim; I 1. The method of ammonolyzing an organic silicon halide ofthe formula RnSiHah-n wherein R is an organic monovalent radicalattached to the silicon by a silicon-to-carbon bond and being a memberof the group consisting of unsubstituted and alkoxy-substitutedmonovalent hydrocarbon radicals, Hal is a halogen atom attached to asilicon atom, and n is ous ammonia and gaseous primary amine whereintheamino group. is the sole functional group, by simultaneously introducingcontrolled streams of said dissolved organic silicon halide and of anexcess of said gaseous nitrogen compound into a reaction vessel in theabsence of water and at a temperature below room temperature, andmaintaining the temperature of the reaction by adjusting the reactantsupply so as to maintain an excess of said gaseous nitrogen compounduntil said reaction is substantially complete.-

silicon halide of the formula RnSiHElh-n wherein R is an aliphaticmonovalent radical attached to the silicon by a silicon-to-carbon bondand being a member of the group consisting of unsubstituted andalkoxy-substituted monovalent hydrocarbon radicals, Hal is a halogenatom, and n is an integer from 1 to 2, comprising dissolving saidaliphatic silicon halide in an ether inert toward said organic siliconhalide, contacting said dissolved organic silicon halide with anammonolyzing gaseous nitrogen 3, compound selected from the classconsisting of gaseous ammonia and gaseous primary amine wherein theamino group is the sole functional group, by simultaneously introducingcontrolled streams of said dissolved organic silicon halide and of anexcess of said gaseous nitrogen compound into a reaction vessel in theabsence of water and at a temperature below room tem perature and abovethe boiling point of said ammonolyzing compound, and maintaining thetemperature of. the reaction by adjusting the reactant supply so as tomaintain an excess of said gaseous nitrogen compound until said reactionis substantially complete? 3. The method of ammonolyzing an organicsilicon halide of the formula RnSiHak-n wherein R is an aromatic radicalbeing a member of the group consisting of unsubstituted andalkoxy-sub'stituted monovalent aromatic hydrocarbon radicals, Hal is ahalogen atom, and n is an integer from 1 to 2, comprising dissolvingsaid aromatic silicon halide in a hydrocarbon solvent inert toward saidorganic silicon halide, reacting said dissolved organic silicon halidewith an ammonolyzing gaseous nitrogen compound selected from the classconsisting of gaseous ammonia and gaseous primary amine wherein theamino group is the sole functional group, by simultaneously introducingcontrolled streams of said dissolved organic silicon halide and of anexcess of said gaseous nitrogen compound into a reaction vessel in theabsence of water and at a temperature belowroom temperature and abovethe boiling point of said ammonolyzing compound, and maintaining thetemperature of the reaction by adjusting the reactant supply so as tomaintain an excess of said gaseous nitrogen compound until said reactionis substantially complete.

4. The method of ammonolyzing an organic silicon halide of the formulaRnSiHa14-n wherein R is an aromatic radical being a member of the groupconsisting of unsubstituted and alkoxy-substituted monovalent aromatichydrocarbon radicals, Hal is a halogen atom, and n is an integer from 1to 2, comprising dissolving said aromatic silicon halide in an aromaticsolvent inert toward said organic silicon halide, said solvent beingselected from the group consisting of xylene and toluene, reacting saiddissolved organic silicon halide with an ammonolyzing gaseous nitrogencompound selected from the class consisting of gaseous ammonia andgaseous primary amine wherein the amino group is the sole functionalgroup, by simultaneously introducing controlled streams of saiddissolved organic silicon halide and of an ex- 10 cess of said gaseousnitrogen compound into a reaction vessel in the absence of water and at-a temperature below room temperature and above the boiling point ofsaid ammonolyzing compound, and maintaining the temperature of thereaction by adjusting the reactant supply so as to maintain an excess ofsaid gaseous nitrogen compound until said reaction is substantiallycomplete.

5. The method of ammonolyzing an organic silicon halide of the formulawherein'R is an unsaturated alkyl radical, Hal is a halogen atomattached to a silicon atom, and TL is an integer from 1 to 2, comprisingdissolving said organic silicon halide in an organic solvent inerttowards said organic silicon halide, reacting said dissolved organicsilicon halide in the absence of water and at a temperature below roomtemperature with an ammonolyzing gaseous nitrogen compound selected fromthe class consisting of gaseous ammonia and gaseous primary aminewherein the amino group is the sole functional group, by simultaneouslyintroducing controlled streams of said dissolved organic silicon halideand of an excess of said gaseous nitrogen compound into a reactionvessel and maintaining the temperature of the reaction by adjusting thereactant supply so as to maintain an excess of said gaseous nitrogencompound until said reaction is substantially complete.

6. The method of ammonolyzing an organic silicon halide of the formulaRnslHah-n wherein R is an alkoxy-substituted aromatic radical, Hal is ahalogen atom attached to a silicon atom, and n is an integer from 1 to2, comprising dissolving said organic silicon halide in an organicsolvent inert towards said organic silicon halide, reacting saiddissolved organic silicon halide in the absence of water and at atemperature below room temperature with an ammonolyzing gaseous nitrogencompound selected from the class consisting of gaseous ammonia andgaseous primary amine wherein the amino group is the sole functionalgroup, by simultaneously introducing controlled streams of saiddissolved organic silicon halide and of an excess of said gaseousnitrogen compound into a reaction vessel and maintaining the temperatureof the reaction by adjusting the reactant supply so as to maintain anexcess of said gaseous nitrogen compound until s'aid reaction issubstantially complete.

7. The method of ammonolyzing an organic silicon halide of the formulaRnSiHaLi-n wherein R is a long-chain saturated alkyl radical with atleast eight carbon atoms, Hal is a, halogen atom attached to a siliconatom, and n is an integer from 1 to 2, comprising dissolving saidorganic silicon halide in an organic solvent inert toward said organicsilicon halide, reacting said dissolved organic silicon halide in theabsence of water and at a temperature below room temperature with anammonolyzing gaseous nitrogen compound selected from the classconsisting of gaseous ammonia and gaseous primary amine wherein theamino group is the sole functional group, by simultaneously introducingcontrolled streams of said dissolved said gaseous nitrogen compounduntil said organic silicon halide and of an excess of said gaseousnitrogen compound into a reaction ves-- sel and maintaining thetemperature of the re- RnsiHah-a wherein R is a cyclic hydrocarbonradical, Hal is a halogen atom attached to a silicon atom, and n is aninteger from 1 to 2, comprising dissolving said organic silicon halidein an organic solvent inert toward said organic silicon halide,

reacting said dissolved organic silicon halide in the absence of waterand at a temperature below room temperature with an ammonolyzmg gaseousnitrogen compound selected from the class consisting of gaseous ammoniaand gaseous primary amine wherein the amino group is the sole,functional group, by simultaneously introducing controlled streams ofsaid dissolved organic silicon halide and of an excess of said gaseousnitrogen compound into a reaction vessel and maintaining the temperatureof the reaction below room temperature by adjusting the reactant supplysoas to maintain an excess of said gaseous nitrogen .compound until saidreaction is substantially complete.

9. The method of ammonolyzing a fully substituted organic silicon halideoi the formula RnSiHah-n wherein R is a mondvalent'brganic radical at-.

tached to the silicon by a silicon-to-carbon 'bond and being a, memberof the group conintroduction into a reaction vessel controlled streamsof said silicon halide and of an excess of a gaseous ammonolyzingnitrogen compound having at least two replaceable hydrogen atoms at atemperature below C., the silicon compound being dissolved in an inertorganic solvent, and separating the ammonolyzed reaction product fromthe excess reactants and byproducts.

10. The method of ammonolyzing a fully substituted organic siliconhalide of the formula RnSiHal4 n, wherein R is a monovalent organicradical attached to the silicon by a silicon-tocarbon bond and being amember of the group consisting of monovalent unsubstituted andalkoxy-substituted hydrocarbon radicals, Hal is a halogen atom and n isan integer from 1 to 2, comprising slowly contacting by simultaneous l2.introduction into' a reaction vessel controlled streams of said siliconhalide and of an excess of gaseous ammonia at a temperature below 0, C.,the silicon compound being dissolved in 5 an inert organic solvent, andseparating the ammonolyzed reaction product from the excess reactantsand from the ammonium halide also formed. f

11. The method according toclaim 10, wherein said inert organic solventis ether.

- I 12. A polymeric resin characterized, by I re-,

peating units of silicon linked to nitrogen as an integral part of thepolymer chain in which the repeating units consist of siliconsubstituted by at least one monovalent alkoxy-substituted aromaticradical, said silicon being attached to nitrogen substituted by a memberof the group consisting of hydrogen and hydrocarbon radicals, said resinhaving an-average ratio 01' one atom of silicon to approximately 1.5atoms of nitrogen in its repeating 13. A- polymeric resin characterizedby repeating units of silicon linked to nitrogen as an integral part ofthe polymer chain in which the repeating-units consist of siliconsubstituted I by a -p-anisy'l radical, said silicon being attached tonitrogen substituted by a member of the group consisting of hydrogen andhydrocarbon radicals, said resin having an average ratio of one atom ofsilicon to approximately 1.5 atoms ofnitrogen in its repeating 14. A.polymeric resin characterized by repeating units of silicon linked tonitrogen as an integral part of the polymer chain in which 5 therepeating units consist of silicon substituted by a p-ethoxy phenylradical, said silicon being attached to nitrogen substituted by a memberof the group consisting of hydrogen and hydrocarbon radicals, saidresinhaving an 40 average ratio of one atom of silicon to approximately1.5 atoms of nitrogeninits repeating units.

NICHOLAS D. CHERONIS.

REFERENCES CITED I The following references are of record in the fileof. this patent: v

UNITED STATES PATENTS vol. 156, 1923, pp. 986 and 992 to 997.

Sauer: Jour. Amer. Chem. Soc., vol. 66, 1944,

1. THE METHOD OF AMMONOLYZING AN ORGANIC SILICON HALIDE OF THE FORMULA